The invention pertains to digital data processing and, more particularly, to networks and methods of operation thereof. The invention has application, for example, in managing mixed-protocol or heterogeneous storage area networks.
In early computer systems, long-term data storage was typically provided by dedicated storage devices, such as tape and disk drives, connected to a data central computer. Requests to read and write data generated by application programs were processed by special-purpose input/output routines resident in the computer operating system. With the advent of “time sharing” and other early multiprocessing techniques, multiple users could simultaneously store and access data-albeit only through the dedicated storage devices.
With the rise of the personal computer (and workstation) in the 1980's, demand by business users led to development of interconnection mechanisms that permitted otherwise independent computers to access data on one another's storage devices. Though computer networks had been known prior to this, they typically permitted only communications, not storage sharing.
The prevalent business network that has emerged is the local area network, typically comprising “client” computers (e.g., individual PCs or workstations) connected by a network to a “server” computer. Unlike the early computing systems in which all processing and storage occurred on a central computer, client computers usually have adequate processor and storage capacity to execute many user applications. However, they often rely on the server computer—and its associated battery of disk drives and storage devices—for other than short-term file storage and for access to shared application and data files.
An information explosion, partially wrought by the rise of the corporate computing and, partially, by the Internet, is spurring further change. Less common are individual servers that reside as independent hubs of storage activity. Often many storage devices are placed on a network or switching fabric that can be accessed by several servers (such as file servers and web servers) which, in turn, service respective groups of clients. Sometimes even individual PCs or workstations are enabled for direct access of the storage devices (though, in most corporate environments such is province of server-class computers) on these storage area networks or SANs.
To date, most of the focus of SAN management has been on providing solutions for networks that operate under the fiber channel protocol (FCP). However, storage area devices that operate under different protocols, notably, SCSI-like storage devices that operate under the Internet Protocol (IP), are becoming increasingly popular. The disparity of these protocols and components operating under them presents a challenge for network management, which is only further complicated by the existence of devices (such as gateway) that themselves may operate under multiple protocols.